In the past, commercially available denim garments have been of two basic types, one stiff but offering the look of a new garment and the other soft and giving the appearance of a used garment. In one type the denim fabric was treated with a starch finish on top of the size used for weaving the fabric, after which the fabric was shrunk to produce less than 3% shrinkage in both warp and fill directions. The finished denim was cut and sewn into garments which were sold in this condition. Alternatively, the garments were washed prior to sale to soften. Both of these garments are described as preshrunk, which indicates they are stable against laundry shrinkage. The unwashed garment offers the uniform look of a new garment but is stiff. The washed garment is soft but has the appearance of being used.
Attempts to process denim through conventional shrinkage stabilization processes, such as Sanforization.RTM. (compressive shrinkage) without use of any size have failed since, in practice, fabric is backwound off a roll before it is cut and sewn. Tension on the fabric during backwinding elongates the fabric and causes excessive shrinkage. Partial removal of the weave size and starch (leaving 1.5%-3.5% non-fibrous material) gives some improvement but the garments are still stiff compared with washed garments.